How to upgrade Windows 10 Home to Pro without product key?

Using the Registry Modification + In-Place Upgrade method is a documented, albeit unofficial, technical workaround that aims to let you upgrade Windows 10 Home to Pro without key.

This method relies on a known technique that modifies specific registry entries to "trick" the Windows setup program.

The core steps involve changing the following values in the Registry Editor (regedit) under the key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion (and also in the Wow6432Node subkey):

• EditionID: Change the value from Core (which signifies Home) to Professional.
• ProductName: Change the value from something like Windows 10 Home to Windows 10 Professional.

After making these changes, you would launch an in-place upgrade by running the setup.exe from Windows 10/11 Pro installation media directly from your desktop. The altered registry values are meant to convince the installer that it's permissible to perform an edition switch while keeping your apps and files.

To upgrade Windows 10 Home to Pro without key, as described in the search results, is that when you run the Pro installer, it will eventually prompt you to enter a valid Windows 10 Pro product key. You cannot proceed without one. Some users have noted that this registry trick may only change the label that appears in the system information, without actually unlocking all the Pro features, leaving your system effectively still a Home version with a different name.